Q: Which equation is used to calculate the equilibrium potential for a single ion across a membrane?

The Nernst equation: $$E = \frac{RT}{zF} \ln \left( \frac{[\text{ion}]_{\text{outside}}}{[\text{ion}]_{\text{inside}}} \right)$$

Question 1

Which of the following best describes the resting membrane potential of a typical neuron?

Accepted Answer

It is the electrical potential difference across the membrane when the cell is not actively transmitting signals, typically ranging from -40 to -90 mV.

Question 2

Which equation is used to calculate the equilibrium potential for a single ion across a membrane?

Accepted Answer

The Nernst equation: $$E = \frac{RT}{zF} \ln \left( \frac{[	ext{ion}]_{	ext{outside}}}{[	ext{ion}]_{	ext{inside}}} ight)$$

Question 3

A neuron is more permeable to K+ than Na+ at rest. What is the primary reason for this?

Accepted Answer

There are more open K+ leak channels than Na+ leak channels in the resting membrane.

Question 4

If the extracellular concentration of K+ increases significantly (hyperkalemia), what effect does this have on the resting membrane potential?

Accepted Answer

The resting membrane potential becomes less negative (depolarizes).

Question 5

Which of the following is NOT a function of glial cells in the nervous system?

Accepted Answer

Transmitting electrical signals over long distances.

Question 6

Which part of the neuron is primarily responsible for receiving incoming signals from other cells?

Accepted Answer

Dendrites

Question 7

Which of the following best describes the role of the Na+/K+ ATPase in maintaining the resting membrane potential?

Accepted Answer

It actively transports 3 Na+ out and 2 K+ in, maintaining concentration gradients and generating a negative intracellular charge.

Question 8

Which subdivision of the nervous system is responsible for controlling involuntary actions such as heart rate and digestion?

Accepted Answer

Autonomic nervous system

Question 9

A patient presents with hypokalemia (low extracellular K+). What is the expected effect on the neuron’s resting membrane potential?

Accepted Answer

The resting membrane potential becomes more negative (hyperpolarizes).

Question 10

Which of the following best explains why the equilibrium potential for K+ ($$E_{K^+}) is $$negative in most cells?

Accepted Answer

K+ concentration is higher inside the cell than outside, so K+ tends to leave the cell, making the inside more negative.

Question 11

Which of the following is a correct description of the organization of the nervous system?

Accepted Answer

The central nervous system (CNS) consists of the brain and spinal cord, while the peripheral nervous system (PNS) includes all nerve tissue outside the CNS.

Question 12

Which of the following scenarios would most likely result in depolarization of a neuron?

Accepted Answer

Opening of Na+ channels, allowing Na+ to enter the cell.

Question 13

Which formula would you use to calculate the membrane potential when the cell is permeable to multiple ions?

Accepted Answer

Goldman-Hodgkin-Katz equation: $$V_m = \frac{RT}{F} \ln \left( \frac{P_{K^+}[K^+]_{	ext{outside}} + P_{Na^+}[Na^+]_{	ext{outside}} + P_{Cl^-}[Cl^-]_{	ext{inside}}}{P_{K^+}[K^+]_{	ext{inside}} + P_{Na^+}[Na^+]_{	ext{inside}} + P_{Cl^-}[Cl^-]_{	ext{outside}}} ight)$$

Question 14

Which of the following is TRUE regarding sensory neurons?

Accepted Answer

They carry information about stimuli such as temperature, pressure, and light to the CNS.

Question 15

A neuron’s axon terminal is primarily involved in which function?

Accepted Answer

Transmitting signals to target cells via neurotransmitter release.

Question 16

Which of the following would most likely cause hyperpolarization of a neuron?

Accepted Answer

Opening of K+ channels, allowing K+ to leave the cell.

Question 17

Which of the following best describes the function of efferent neurons?

Accepted Answer

They carry information away from the CNS to effectors such as muscles and glands.

Question 18

Which of the following is a real-world consequence of a disturbance in the membrane potential due to altered ion permeability?

Accepted Answer

A sudden increase in Na+ permeability can lead to neuronal depolarization and trigger an action potential.

Question 19

Which of the following statements about nerves is correct?

Accepted Answer

Nerves are bundles of peripheral neurons that can be sensory, motor, or mixed.

Neurophysiology: Membrane Potential and Organization of the Nervous System N1

Study Guide - Practice Questions

Study Guide - Flashcards